Fluid filters have been in use for many years and are available in numerous forms. The present invention relates to that type of filter having a removable filter element or screen. These are sometimes referred to as disc filters due to their configuration. One example of a prior art filter may be seen in U.S. Pat. No. 3,485,376, Petersen et al., of Dec. 23, 1969. This patent specification discloses a disc type filter using a plurality of separate sections and separable components therein.
U.S. Pat. No. 3,028,012, Billner, Apr. 3, 1962, illustrates a sandwich type of filter, having fluid inlet and outlets to the filter on opposite sides of the filter body.
U.S. Pat. No. 4,446,017, May 1, 1984, Oberg, illustrates a sandwich type of filter utilizing a removable filter element of wire screen. The filter has upper and lower halves which, together, clamp the filter element therebetween. The path taken by the fluid to the filter interior is such that the fluid enters the filter on one side of the filter body and exits through an outlet opening on the opposite side of the filter body.
Another example of the prior art is shown in Canadian Patent 891,031, Forster, of Jan. 18, 1972. This specification discloses a plate for a filter press in which a slanted interior wall is utilized to facilitate filter cake removable by gravity. An interior gasket is mounted within a groove extending along the slanted wall to mount the filter cloth within the peripheral edges of the filter plate to eliminate wear of the filter cloth.
In the examples of prior art listed above, fluid to the filter enters one side of the filter body and leaves on an opposite side. With such arrangements, removing the filter element for either with a fresh element or for cleaning, and re-installation if it is a reusable element, requires removal of at least one hose from one side of the filter. This disrupts the fluid circuitry and requires expensive hoses and hydraulic hardware. Other disadvantages result from having the fluid entrance on one side of the body and the fluid exit on the other, not the least of which is the difficulty in using fixed piping for a reduction in maintenance and safety risks.